U.S. patent application number 16/374937 was filed with the patent office on 2020-10-08 for redundant systems for vehicle critical systems.
The applicant listed for this patent is Hamilton Sundstrand Corporation. Invention is credited to Peter AT Cocks, John S. Murphy, Matthew Pess, Jonathan Rheaume.
Application Number | 20200317361 16/374937 |
Document ID | / |
Family ID | 1000004040055 |
Filed Date | 2020-10-08 |
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United States Patent
Application |
20200317361 |
Kind Code |
A1 |
Pess; Matthew ; et
al. |
October 8, 2020 |
REDUNDANT SYSTEMS FOR VEHICLE CRITICAL SYSTEMS
Abstract
Redundant electrochemical systems and methods for vehicles are
described. The systems include a first electrochemical device
located at a first position on the vehicle wherein the first
electrochemical device is configured to generate at least one of
inert gas, oxygen, and electrical power and a second
electrochemical device located at a second position on the vehicle
wherein the second electrochemical device is configured to generate
at least one of inert gas, oxygen, and electrical power. The first
electrochemical device is configured to operate in a first mode
during normal operation of the vehicle and a second mode when the
second electrochemical device fails, wherein in the second mode,
the first electrochemical device provides the at least one of inert
gas, oxygen, and electrical power for at least one vehicle critical
system of the vehicle.
Inventors: |
Pess; Matthew; (West
Hartford, CT) ; Rheaume; Jonathan; (West Hartford,
CT) ; Murphy; John S.; (Wilbraham, MA) ;
Cocks; Peter AT; (South Glastonbury, CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hamilton Sundstrand Corporation |
Charlotte |
NC |
US |
|
|
Family ID: |
1000004040055 |
Appl. No.: |
16/374937 |
Filed: |
April 4, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B64D 37/32 20130101;
B01D 2259/4575 20130101; B01D 53/326 20130101 |
International
Class: |
B64D 37/32 20060101
B64D037/32; B01D 53/32 20060101 B01D053/32 |
Claims
1. A redundant electrochemical system for vehicles, the system
comprising: a first electrochemical device located at a first
position on the vehicle wherein the first electrochemical device is
configured to generate at least one of inert gas, oxygen, and
electrical power; and a second electrochemical device located at a
second position on the vehicle wherein the second electrochemical
device is configured to generate at least one of inert gas, oxygen,
and electrical power; wherein the first electrochemical device is
configured to operate in a first mode during normal operation of
the vehicle and a second mode when the second electrochemical
device fails, wherein in the second mode, the first electrochemical
device provides the at least one of inert gas, oxygen, and
electrical power for at least one vehicle critical system of the
vehicle.
2. The system of claim 1, wherein the second electrochemical device
is configured to operate in a first mode during normal flight and a
second mode when the first electrochemical device fails, wherein in
the second mode of the second electrochemical device, the second
electrochemical device provides the at least one of inert gas,
oxygen, and electrical power for at least one vehicle critical
system of the vehicle.
3. The system of claim 1, further comprising at least one
additional electrochemical device, wherein the at least one
additional electrochemical device is configured to operate in a
first mode during normal flight and a second mode when at least one
of the first electrochemical device and the second electrochemical
device fails, wherein in the second mode, the at least one
additional electrochemical device provides the at least one of
inert gas, oxygen, and electrical power for at least vehicle
critical system of the vehicle.
4. The system of claim 1, wherein at least one of the first
electrochemical device and the second electrochemical device is a
PEM inerting system having: an electrochemical cell comprising a
cathode and an anode separated by a separator comprising an ion
transfer medium; a cathode fluid flow path in operative fluid
communication with a catalyst at the cathode between a cathode
fluid flow path inlet and a cathode fluid flow path outlet; a
cathode supply fluid flow path between a cathode supply gas source
and the cathode fluid flow path inlet; an anode fluid flow path in
operative fluid communication with a catalyst at the anode,
including an anode fluid flow path outlet; an electrical connection
to a power source or power sink; and an inerting gas flow path in
operative fluid communication with the cathode flow path outlet and
the cathode supply gas source.
5. The system of claim 1, wherein the first location and the second
location are substantially the same location.
6. The system of claim 5, wherein the first location is within or
proximate a cargo hold of the vehicle.
7. The system of claim 1, wherein the first location and the second
location are different.
8. The system of claim 7, wherein the first location is within or
proximate a cargo hold of the vehicle and the second location is
within or on a wing of the vehicle.
9. The system of claim 1, wherein the at least one vehicle critical
system comprises a fuel tank inerting system, a fire suppression
system, a life support system, and/or an emergency electrical power
system.
10. The system of claim 1, wherein the first and the second
electrochemical devices are each fluidly connected to a common
inert gas distribution manifold to supply inert gas to fuel tank
ullages of one or more fuel tanks of the vehicle.
11. The system of claim 10, further comprising a valve located
within the common inert gas distribution manifold to control a
fluid connection between the first electrochemical device and a
fire suppression, wherein the valve is closed in the first mode and
open in the second mode.
12. The system of claim 1, wherein the first and the second
electrochemical devices are each fluidly connected to a common
O.sub.2 distribution manifold to supply oxygen to a life support
system of the vehicle.
13. The system of claim 1, wherein the first and the second
electrochemical devices are each electrically connected to an
electrical bus to supply electrical power to one or more electrical
components of the vehicle.
14. The system of claim 1, wherein each of the first and second
electrochemical devices is fluidly connected to a fire suppression
of the vehicle, the system further comprising: a valve arranged to
control the fluid connection between the first electrochemical
device and the fire suppression, wherein the valve is closed in the
first mode and open in the second mode.
15. The system of claim 1, wherein at least one of the first
electrochemical device and the second electrochemical device is a
solid oxide (SO) electrochemical gas separator.
16. The system of claim 1, wherein the vehicle is an aircraft.
17. A method of generating at least one of inerting gas, oxygen,
and electrical power on a vehicle, wherein a first electrochemical
device is located at a first position on the vehicle wherein the
first electrochemical device is configured to generate at least one
of inert gas, oxygen, and electrical power and a second
electrochemical is device located at a second position on the
vehicle wherein the second electrochemical device is configured to
generate at least one of inert gas, oxygen, and electrical power,
the method comprising: operating the first electrochemical device
in a first mode to generate the at least one of inert gas, oxygen,
and electrical power; operating the second electrochemical device
in a first mode to generate the at least one of inert gas, oxygen,
and electrical power; and operating the first electrochemical
device in a second mode, when the second electrochemical device
fails, wherein in the second mode, the first electrochemical device
generates the at least one of inert gas, oxygen, and electrical
power for at least one of vehicle critical system of the
vehicle.
18. The method of claim 17, wherein the vehicle is an aircraft.
19. The method of claim 17, wherein the at least one vehicle
critical system comprises a fuel tank inerting system, a fire
suppression system, a life support system, and/or an emergency
electrical power system.
20. The method of claim 17, wherein the first electrochemical
device is one of a proton exchange membrane and a solid oxide
electrolyte electrochemical device.
Description
BACKGROUND
[0001] The subject matter disclosed herein generally relates to
systems for generating and providing inert gas, oxygen, and/or
power on vehicles (e.g., aircraft, military vehicles, heavy
machinery vehicles, sea craft, ships, submarines, etc.), and, more
particularly, to redundant systems for vehicle critical
systems.
[0002] It is recognized that fuel vapors within fuel tanks become
combustible or explosive in the presence of oxygen. An inerting
system decreases the probability of combustion or explosion of
flammable materials in a fuel tank by maintaining a chemically
non-reactive or inerting gas, such as nitrogen-enriched air, in the
fuel tank vapor space, also known as ullage. Three elements are
required to initiate combustion or an explosion: an ignition source
(e.g., heat), fuel, and oxygen. The oxidation of fuel may be
prevented by reducing any one of these three elements. If the
presence of an ignition source cannot be prevented within a fuel
tank, then the tank may be made inert by: 1) reducing the oxygen
concentration, 2) reducing the fuel concentration of the ullage to
below the lower explosive limit (LEL), or 3) increasing the fuel
concentration to above the upper explosive limit (UEL). Many
systems reduce the risk of oxidation of fuel by reducing the oxygen
concentration by introducing an inerting gas such as
nitrogen-enriched air (NEA) (i.e., oxygen-depleted air or ODA) to
the ullage, thereby displacing oxygen with a mixture of nitrogen
and oxygen at target thresholds for avoiding explosion or
combustion.
[0003] It is known in the art to equip vehicles (e.g., aircraft,
military vehicles, etc.) with onboard inerting gas generating
systems, which supply nitrogen-enriched air to the vapor space
(i.e., ullage) within the fuel tank. The nitrogen-enriched air has
a substantially reduced oxygen content that reduces or eliminates
oxidizing conditions within the fuel tank. Onboard inerting gas
generating systems typically use membrane-based gas separators.
Such separators contain a membrane that is permeable to oxygen and
water molecules, but relatively impermeable to nitrogen molecules.
A pressure differential across the membrane causes oxygen molecules
from air on one side of the membrane to pass through the membrane,
which forms oxygen-enriched air (OEA) on the low-pressure side of
the membrane and nitrogen-enriched air (NEA) on the high-pressure
side of the membrane. The requirement for a pressure differential
necessitates a source of compressed or pressurized air.
[0004] One type of membrane-based electrochemical gas separator is
a Proton Exchange Membrane (PEM). In one mode of operation, the PEM
is an electrolytic gas generator that requires deionized (DI)
water, electric power, and air to produce streams of inert gas and
oxygen. In another mode of operation, the PEM is operated as a fuel
cell that requires hydrogen and oxygen to generate electric power
and inert gas. Another type of electrochemical gas separator
utilizes a Solid Oxide (SO) electrolyte. In one mode of operation,
the SO device is an electrolytic gas generator that requires
electric power and air to produce streams of inert gas and oxygen.
In another mode of operation, the SO device is operated as a fuel
cell that requires fuel, such as hydrogen and carbon monoxide, as
well as oxygen to generate power and inert gas.
BRIEF DESCRIPTION
[0005] According to some embodiments, redundant electrochemical
systems for vehicles are provided. The systems include a first
electrochemical device located at a first position on the vehicle
wherein the first electrochemical device is configured to generate
at least one of inert gas, oxygen, and electrical power and a
second electrochemical device located at a second position on the
vehicle wherein the second electrochemical device is configured to
generate at least one of inert gas, oxygen, and electrical power.
The first electrochemical device is configured to operate in a
first mode during normal operation of the vehicle and a second mode
when the second electrochemical device fails, wherein in the second
mode, the first electrochemical device provides the at least one of
inert gas, oxygen, and electrical power for at least one vehicle
critical system of the vehicle.
[0006] In addition to one or more of the features described herein,
or as an alternative, further embodiments of the systems may
include that the second electrochemical device is configured to
operate in a first mode during normal flight and a second mode when
the first electrochemical device fails, wherein in the second mode
of the second electrochemical device, the second electrochemical
device provides the at least one of inert gas, oxygen, and
electrical power for at least one vehicle critical system of the
vehicle.
[0007] In addition to one or more of the features described herein,
or as an alternative, further embodiments of the systems may
include at least one additional electrochemical device, wherein the
at least one additional electrochemical device is configured to
operate in a first mode during normal flight and a second mode when
at least one of the first electrochemical device and the second
electrochemical device fails, wherein in the second mode, the at
least one additional electrochemical device provides the at least
one of inert gas, oxygen, and electrical power for at least vehicle
critical system of the vehicle.
[0008] In addition to one or more of the features described herein,
or as an alternative, further embodiments of the systems may
include that at least one of the first electrochemical device and
the second electrochemical device is a PEM inerting system. The PEM
inerting system includes an electrochemical cell comprising a
cathode and an anode separated by a separator comprising an ion
transfer medium, a cathode fluid flow path in operative fluid
communication with a catalyst at the cathode between a cathode
fluid flow path inlet and a cathode fluid flow path outlet, a
cathode supply fluid flow path between a cathode supply gas source
and the cathode fluid flow path inlet, an anode fluid flow path in
operative fluid communication with a catalyst at the anode,
including an anode fluid flow path outlet, an electrical connection
to a power source or power sink, and an inerting gas flow path in
operative fluid communication with the cathode flow path outlet and
the cathode supply gas source.
[0009] In addition to one or more of the features described herein,
or as an alternative, further embodiments of the systems may
include that the first location and the second location are
substantially the same location.
[0010] In addition to one or more of the features described herein,
or as an alternative, further embodiments of the systems may
include that the first location is within or proximate a cargo hold
of the vehicle.
[0011] In addition to one or more of the features described herein,
or as an alternative, further embodiments of the systems may
include that the first location and the second location are
different.
[0012] In addition to one or more of the features described herein,
or as an alternative, further embodiments of the systems may
include that the first location is within or proximate a cargo hold
of the vehicle and the second location is within or on a wing of
the vehicle.
[0013] In addition to one or more of the features described herein,
or as an alternative, further embodiments of the systems may
include that the at least one vehicle critical system comprises a
fuel tank inerting system, a fire suppression system, a life
support system, and/or an emergency electrical power system.
[0014] In addition to one or more of the features described herein,
or as an alternative, further embodiments of the systems may
include that the first and the second electrochemical devices are
each fluidly connected to a common inert gas distribution manifold
to supply inert gas to fuel tank ullages of one or more fuel tanks
of the vehicle.
[0015] In addition to one or more of the features described herein,
or as an alternative, further embodiments of the systems may
include a valve located within the common inert gas distribution
manifold to control a fluid connection between the first
electrochemical device and a fire suppression, wherein the valve is
closed in the first mode and open in the second mode.
[0016] In addition to one or more of the features described herein,
or as an alternative, further embodiments of the systems may
include that the first and the second electrochemical devices are
each fluidly connected to a common O.sub.2 distribution manifold to
supply oxygen to a life support system of the vehicle.
[0017] In addition to one or more of the features described herein,
or as an alternative, further embodiments of the systems may
include that the first and the second electrochemical devices are
each electrically connected to an electrical bus to supply
electrical power to one or more electrical components of the
vehicle.
[0018] In addition to one or more of the features described herein,
or as an alternative, further embodiments of the systems may
include that each of the first and second electrochemical devices
is fluidly connected to a fire suppression of the vehicle. The
system further includes a valve arranged to control the fluid
connection between the first electrochemical device and the fire
suppression, wherein the valve is closed in the first mode and open
in the second mode.
[0019] In addition to one or more of the features described herein,
or as an alternative, further embodiments of the systems may
include that at least one of the first electrochemical device and
the second electrochemical device is a solid oxide (SO)
electrochemical gas separator.
[0020] In addition to one or more of the features described herein,
or as an alternative, further embodiments of the systems may
include that the vehicle is an aircraft.
[0021] According to some embodiments, methods of generating at
least one of inerting gas, oxygen, and electrical power on a
vehicle are provided. A first electrochemical device is located at
a first position on the vehicle wherein the first electrochemical
device is configured to generate at least one of inert gas, oxygen,
and electrical power and a second electrochemical device is located
at a second position on the vehicle wherein the second
electrochemical device is configured to generate at least one of
inert gas, oxygen, and electrical power. The methods include
operating the first electrochemical device in a first mode to
generate the at least one of inert gas, oxygen, and electrical
power, operating the second electrochemical device in a first mode
to generate the at least one of inert gas, oxygen, and electrical
power, and operating the first electrochemical device in a second
mode, when the second electrochemical device fails, wherein in the
second mode, the first electrochemical device generates the at
least one of inert gas, oxygen, and electrical power for at least
one of vehicle critical system of the vehicle.
[0022] In addition to one or more of the features described herein,
or as an alternative, further embodiments of the methods may
include that the vehicle is an aircraft.
[0023] In addition to one or more of the features described herein,
or as an alternative, further embodiments of the methods may
include that the at least one vehicle critical system comprises a
fuel tank inerting system, a fire suppression system, a life
support system, and/or an emergency electrical power system.
[0024] In addition to one or more of the features described herein,
or as an alternative, further embodiments of the methods may
include that the first electrochemical device is one of a proton
exchange membrane and a solid oxide electrolyte electrochemical
device.
[0025] The foregoing features and elements may be combined in
various combinations without exclusivity, unless expressly
indicated otherwise. These features and elements as well as the
operation thereof will become more apparent in light of the
following description and the accompanying drawings. It should be
understood, however, that the following description and drawings
are intended to be illustrative and explanatory in nature and
non-limiting.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The following descriptions should not be considered limiting
in any way. With reference to the accompanying drawings in which
like elements are numbered alike:
[0027] FIG. 1A is a schematic illustration of an aircraft that can
incorporate various embodiments of the present disclosure;
[0028] FIG. 1B is a schematic illustration of a bay section of the
aircraft of FIG. 1A;
[0029] FIG. 2 is a schematic depiction an example embodiment of an
electrochemical cell;
[0030] FIG. 3 is a schematic illustration of an example embodiment
of an electrochemical inerting system that may incorporate
embodiments of the present disclosure;
[0031] FIG. 4 is a schematic illustration of an example embodiment
of an Proton Exchange Membrane (PEM) electrochemical cell inerting
system that may incorporate embodiments of the present
disclosure;
[0032] FIG. 5 is a schematic illustration of a vehicle
incorporating a redundant system in accordance with an embodiment
of the present disclosure;
[0033] FIG. 6 is a schematic illustration of a vehicle
incorporating a redundant system in accordance with an embodiment
of the present disclosure; and
[0034] FIG. 7 is a schematic illustration of a vehicle
incorporating a redundant system in accordance with an embodiment
of the present disclosure
DETAILED DESCRIPTION
[0035] A detailed description of one or more embodiments of the
disclosed apparatuses and methods are presented herein by way of
illustration and exemplification and without limitation with
reference to the Figures.
[0036] As shown in FIGS. 1A-1B, an aircraft includes an aircraft
body 101, which can include one or more bays 103 beneath a center
wing box. The bay 103 can contain and/or support one or more
components of the aircraft 101. For example, in some
configurations, the aircraft can include environmental control
systems and/or fuel inerting systems within the bay 103. As shown
in FIG. 1B, the bay 103 includes bay doors 105 that enable
installation and access to one or more components (e.g.,
environmental control systems, fuel inerting systems, etc.)
installed within or on the aircraft. During operation of
environmental control systems and/or fuel inerting systems of the
aircraft, air that is external to the aircraft can flow into one or
more ram air inlets 107. The outside air (i.e., ram air) may then
be directed to various system components (e.g., environmental
conditioning system (ECS) heat exchangers) within the aircraft.
Some air may be exhausted through one or more ram air exhaust
outlets 109.
[0037] Also shown in FIG. 1A, the aircraft includes one or more
engines 111. The engines 111 are typically mounted on the wings 112
of the aircraft and are connected to fuel tanks (not shown) in the
wings. The engines and/or fuel tanks may be located at other
locations depending on the specific aircraft configuration. In some
aircraft configurations, air can be bled from the engines 111 and
supplied to environmental control systems and/or fuel inerting
systems, as will be appreciated by those of skill in the art.
[0038] Although shown and described above and below with respect to
an aircraft, embodiments of the present disclosure are applicable
to any type of vehicle. For example, military vehicles, heavy
machinery vehicles, sea craft, ships, submarines, etc., may benefit
from implementation of embodiments of the present disclosure. For
example, aircraft and other vehicles having fire suppression
systems, emergency power systems, and other systems that may
electrochemical systems as described herein may include the
redundant systems described herein. As such, the present disclosure
is not limited to application to aircraft, but rather aircraft are
illustrated and described as example and explanatory embodiments
for implementation of embodiments of the present disclosure.
[0039] Referring now to FIG. 2, an electrochemical cell 10 is
schematically depicted. The electrochemical cell 10 comprises a
separator 12 that includes an ion transfer medium. As shown in FIG.
2, the separator 12 has a cathode 14 disposed on one side and an
anode 16 disposed on the other side. The cathode 14 and the anode
16 can be fabricated from catalytic materials suitable for
performing a desired electrochemical reaction (e.g., an
oxygen-reduction reaction at the cathode and an oxidation reaction
at the anode)--i.e., a catalytic reactor inert gas generation
system. Catalytic materials include, but are not limited to,
nickel, platinum, palladium, rhodium, carbon, gold, tantalum,
titanium, tungsten, ruthenium, iridium, osmium, zirconium, alloys
thereof, and the like, as well as combinations of the foregoing
materials. Some organic materials and metal oxides can also be used
as catalysts, as contrasted to electrochemical cells utilizing
proton exchange membranes where the conditions preclude the use of
metal oxide catalysts. Examples of metal oxide catalysts include,
but are not limited to ruthenium oxides, iridium oxides or
transition-metal oxides, generically depicted as M.sub.xO.sub.y,
where x and y are positive numbers capable of forming a stable
catalytic metal oxide such as Co.sub.3O.sub.4.
[0040] The cathode 14 and the anode 16, each including a respective
catalyst 14',16', are positioned adjacent to, and preferably in
contact with, the separator 12 and can be porous metal layers
deposited (e.g., by vapor deposition) onto the separator 12. In
other embodiments, the cathode 14 and the anode 16 can each have
structures comprising discrete catalytic particles adsorbed onto a
porous substrate that is attached to the separator 12.
Alternatively, catalyst particles can be deposited on high surface
area powder materials (e.g., graphite, porous carbons, metal-oxide
particles, etc.) and then these supported catalysts may be
deposited directly onto the separator 12 or onto a porous substrate
that is attached to the separator 12. Adhesion of the catalytic
particles onto a substrate may be by any method including, but not
limited to, spraying, dipping, painting, imbibing, vapor
depositing, combinations of the foregoing methods, and the like.
Alternately, the catalytic particles may be deposited directly onto
opposing sides of the separator 12. In either case, layers of the
cathode 14 and layers of the anode 16 may include a binder
material, such as a polymer, especially one that also acts as an
ionic conductor such as anion-conducting ionomers. In some
embodiments, the layers of the cathode 14 and layers of the anode
16 can be cast from an "ink," which is a suspension of supported
(or unsupported) catalyst, binder (e.g., ionomer), and a solvent
that can be in a solution (e.g., in water or a mixture of
alcohol(s) and water) using printing processes such as screen
printing or ink jet printing.
[0041] The cathode 14 and the anode 16 can be controllably and/or
electrically connected by an electrical circuit 18 to a
controllable electric power system 20. The electric power system
can include a power source, such as DC power rectified from AC
power produced by a generator powered by a gas turbine engine used
for propulsion or by an auxiliary power unit or an aircraft. In
some embodiments, the electric power system 20 can optionally
include a connection to an electric power sink (e.g., one or more
electricity-consuming systems or components onboard the aircraft)
with appropriate switching, power conditioning, and/or power
bus(es) for such on-board electricity-consuming systems or
components, for optional operation in an alternative fuel cell
mode. Inerting gas systems with electrochemical cells that can
alternatively operate to produce nitrogen-enriched air in a
fuel-consuming power production (e.g., fuel cell) mode or a power
consumption mode (e.g., electrolytic cell) are disclosed in U.S.
Patent Application Publication No. 2017/0331131 A1, the disclosure
of which is incorporated herein by reference in its entirety.
[0042] With continued reference to FIG. 2, a cathode supply fluid
flow path 22 directs gas from a fuel tank ullage space (not shown)
into contact with the cathode 14. Oxygen is electrochemically
depleted from air along a cathode fluid flow path 23, and is
discharged as nitrogen-enriched air (NEA) (i.e., oxygen-depleted
air, ODP) to an inerting gas flow path 24 for delivery to an
on-board fuel tank (not shown), or to a vehicle fire suppression
system associated with an enclosed space (not shown), or
controllably to either or both of a vehicle fuel tank or an
on-board fire suppression system.
[0043] An anode fluid flow path 25 is configured to controllably
receive an anode supply fluid from an anode supply fluid flow path
22'. The anode fluid flow path 25 can include water if the
electrochemical cell is configured for proton transfer across the
separator 12 (e.g., a proton exchange membrane (PEM) electrolyte or
phosphoric acid electrolyte). If the electrochemical cell is
configured for oxygen anion transfer across the separator 12 (e.g.,
a solid oxide electrolyte), it can optionally be configured to
receive air along the anode fluid flow path 25. Although not
stoichiometrically required by the electrochemical reactions of the
solid oxide electrochemical cell, airflow to the anode during
power-consumption mode can have the technical effects of diluting
the potentially hazardous pure heated oxygen at the anode, and
providing thermal regulation to the cell. If the system is
configured for alternative operation in a fuel cell mode, the anode
fluid flow path 25 can be configured to controllably also receive
fuel (e.g., hydrogen for a proton-transfer cell, hydrogen or
hydrocarbon reformate for a solid oxide cell). An anode exhaust 26
can, depending on the type of cell and the content of the anode
exhaust 26, be exhausted or subjected to further processing.
Control of fluid flow along these flow paths can be provided
through conduits and valves (not shown), which can be controlled by
a controller 36.
[0044] In some embodiments, the electrochemical cell 10 can operate
utilizing the transfer of protons across the separator 12.
Exemplary materials from which the electrochemical proton transfer
electrolytes can be fabricated include proton-conducting ionomers
and ion-exchange resins. Ion-exchange resins useful as proton
conducting materials include hydrocarbon- and fluorocarbon-type
resins. Fluorocarbon-type resins typically exhibit excellent
resistance to oxidation by halogen, strong acids, and bases. One
family of fluorocarbon-type resins having sulfonic acid group
functionality is NAFION.TM. resins (commercially available from E.
I. du Pont de Nemours and Company, Wilmington, Del.).
Alternatively, instead of an ion-exchange membrane, the separator
12 can be comprised of a liquid electrolyte, such as sulfuric or
phosphoric acid, which may preferentially be absorbed in a
porous-solid matrix material such as a layer of silicon carbide or
a polymer than can absorb the liquid electrolyte, such as
poly(benzoxazole). These types of alternative "membrane
electrolytes" are well known and have been used in other
electrochemical cells, such as phosphoric-acid fuel cells.
[0045] During operation of a proton transfer electrochemical cell
(i.e., Proton Exchange Membrane "PEM") in the electrolytic mode,
water at the anode undergoes an electrolysis reaction according to
the formula:
H.sub.2O.fwdarw.1/2O.sub.2+2H.sup.++2e (1)
[0046] The electrons produced by this reaction are drawn from the
electrical circuit 18 powered by the electric power system 20
connecting the positively charged anode 16 with the cathode 14. The
hydrogen ions (i.e., protons) produced by this reaction migrate
across the separator 12, where they react at the cathode 14 with
oxygen in the cathode flow path 23 to produce water according to
the formula:
1/2O.sub.2+2H.sup.++2e.sup.-.fwdarw.H.sub.2O (2)
[0047] Removal of oxygen from the cathode flow path 23 produces
nitrogen-enriched air exiting the region of the cathode 14. The
oxygen evolved at the anode 16 by the reaction of formula (1) is
discharged as oxygen or an oxygen-enriched air stream as the anode
exhaust 26.
[0048] During operation of a proton transfer electrochemical cell
in a fuel cell mode, fuel (e.g., hydrogen) at the anode undergoes
an electrochemical oxidation according to the formula:
H.sub.2.fwdarw.2H.sup.++2e.sup.- (3)
[0049] The electrons produced by this reaction flow through the
electrical circuit 18 to provide electric power to an electric
power sink (not shown). The hydrogen ions (i.e., protons) produced
by this reaction migrate across the separator 12, where they react
at the cathode 14 with oxygen in the cathode flow path 23 to
produce water according to the formula (2). Removal of oxygen from
the cathode flow path 23 produces nitrogen-enriched air exiting the
region of the cathode 14, which can be supplied to a fuel tank
ullage.
[0050] As mentioned above, the electrolysis reaction occurring at
the positively charged anode 16 requires water, and the ionic
polymers used for a PEM electrolyte perform more effectively in the
presence of water. Accordingly, in some embodiments, a PEM membrane
electrolyte is saturated with water or water vapor. Although the
reactions described in formulae (1) and (2) are stoichiometrically
balanced with respect to water so that there is no net consumption
of water, in practice moisture will be removed by the inerting gas
flow path 24 (either entrained or evaporated into the
nitrogen-enriched air) as it exits from the region of the cathode
14. Accordingly, in some embodiments, water is circulated past or
along the anode 16 along an anode fluid flow path (and optionally
also past the cathode 14). Such water circulation can also provide
cooling for the electrochemical cells. In some embodiments, water
can be provided at the anode from humidity in air along an anode
fluid flow path in fluid communication with the anode. In other
embodiments, the water produced at the cathode 14 can be captured
and recycled to the anode 16 (not shown). It should also be noted
that, although the embodiments are contemplated where a single
electrochemical cell is employed, in practice multiple
electrochemical cells will be electrically connected in series with
fluid flow to the multiple cathode and anode flow paths routed
through manifold assemblies.
[0051] In some embodiments, a controller 36 can be in operative
communication with the electrochemical cell 10 or associated
components (e.g., aspects of the membrane gas separator, and any
associated valves, pumps, compressors, conduits, or other fluid
flow components, and with switches, inverters, regulators, sensors,
and other electrical system components, and any other system
components to selectively operate the inerting gas system). The
control connections can be through wired electrical signal
connections (not shown) or through wireless connections, as will be
appreciated by those of skill in the art, or combinations thereof.
The controller 36 may be configured to monitor and/or control
operation of the electrochemical cell 10 to generate and/or supply
inert gas to various locations on an aircraft.
[0052] Turning now to FIG. 3, there is shown an inerting system 50
with an electrochemical cell stack 52 that receives a cathode
supply feed 22 from a cathode supply gas source 54 such as a
protected space, an aircraft fuel tank ullage space, an aircraft
cargo hold, and an aircraft equipment bay, and is electrically
connected to a power source or sink (not shown). For illustrative
purposes, the cathode supply gas source 54 is shown as an ullage
space in a fuel tank 56 having a vent 58. However, the cathode
supply gas source could also be a cargo hold or an equipment bay,
or other location on an aircraft, as will be appreciated by those
of skill in the art.
[0053] Gas from the cathode supply gas source 54 is directed by a
fan or blower 60 through an optional flame arrestor 62 and optional
gas treatment module 64 to an internal cathode inlet header (not
shown) into one or more cathode fluid flow paths 23 along the
cathodes in the electrochemical cell stack 52. For ease of
illustration, the anode fluid flow through an anode header of the
electrochemical cell stack 52 is not shown in FIG. 3, but can be
configured as described above with respect to FIG. 2 (e.g., fuel or
water feed connections to an anode side of a PEM electrochemical
cell for operation in fuel cell or electrolytic mode,
respectively).
[0054] Various types of gas treatment modules 64 can be utilized,
either integrated into a single module or as separate modules
disposed in series or parallel along the cathode supply fluid flow
path 22. In some embodiments, the gas treatment module 64 can be
configured to remove fuel vapor from the cathode supply gas, or to
remove one or more fuel contaminants from the cathode supply gas,
or to remove other contaminants such as smoke such as from a fire
in a cargo hold if the cathode supply gas source includes a cargo
hold, or any combinations thereof. Examples of gas treatment
modules include membrane separators (e.g., a reverse selective
membrane with a membrane that has greater solubility with fuel
vapor than air) with an optional sweep gas on the side of the
membrane opposite the cathode supply fluid flow path, adsorbents
(e.g., activated carbon adsorbent as a fuel vapor trap), combustors
such as a catalytic oxidation reactor or other combustion reactor,
etc. Examples of gas treatments that can remove contaminants
include any of the above-mentioned gas treatments for removal of
fuel vapor, e.g., adsorbents or catalysts for removal or
deactivation of fuel contaminants such as sulfur-containing
compounds that could poison catalysts in the electrochemical cell,
as well as other treatments such as filters or activated carbon
adsorbers.
[0055] With continued reference to FIG. 3, oxygen-depleted air is
discharged from the cathode side of the electrochemical cells in
the electrochemical cell stack 52 along an inerting gas flow path
24 toward one or more cathode supply gas source(s) 54. In some
embodiments, a water removal module comprising one or more water
removal stations can be disposed between the electrochemical cell
stack 52 and the cathode supply gas source(s) 54. Examples of water
removal modules include heat exchanger condensers 66 (i.e., a heat
exchanger in which removal of heat condenses water vapor to liquid
water, which is separated from the gas stream), membrane
separators, desiccants, etc. In some embodiments or operating
conditions (e.g., on-ground operation), the heat exchanger
condenser 66 may not remove all of the desired amount of water to
be removed. As such, supplemental drying can optionally be
provided. As shown in FIG. 3, the heat exchanger condenser 66 is
cooled by ram air 68 to remove water from the inerting gas and an
additional dryer 70, such as a membrane separator or desiccant, is
configured to remove residual water not removed by the heat
exchanger condenser 66.
[0056] One or more sensors 72, such as humidity sensors,
temperature sensors, and/or oxygen sensors, can be arranged to
monitor the quality of the inerting gas. The sensors 72 can be used
to provide information and enable control when and under what
parameters the inerting gas generation system should be operated.
Additional optional features may be included, without departing
from the scope of the present disclosure. For example, a check
valve 76 and a flame arrestor 78 can be arranged to promote safe
and efficient flow of the inerting gas to the cathode supply gas
source(s) 54.
[0057] Turning to FIG. 4, an example embodiment of an inerting
system 50' with a PEM electrochemical cell 52' onboard an aircraft
is shown. As shown in FIG. 4, air from a compressed air source such
as a compressor section of a turbine fan engine is directed along a
cathode supply fluid flow path 22 to a PEM electrochemical cell
52'. In some embodiments, some of the compressed air can be
diverted to an additional pneumatic load such as an aircraft
environmental control system 82. The hot compressed air is then
passed through a heat exchanger that receives cooling air from a
ram air duct to cool the compressed air to a temperature suitable
for the PEM electrochemical cell 52' (e.g., 50-120.degree. C.). As
illustratively labeled, the PEM electrochemical cell 52' has a
similar structure, components, and labels as that described above,
e.g., with respect to FIGS. 2-3.
[0058] A proton source is directed to the anode side fluid flow
path 25 (e.g., hydrogen gas for operation of the cell in fuel cell
(power production) mode, or water for operation of the cell in
electrolytic (power consumption) mode). A condenser receives wet
inerting gas from the cathode side fluid flow path 24 and cools it
with ram cooling air to condense and remove water 80 from the
inerting gas. The inerting gas is optionally then directed to a
membrane separator 62' with a water-permeable tubular membrane 64'
for removal of additional water 66' and subsequently through a
pressure control device 68' to a fuel tank 56 (or other cathode
supply gas source such as a cargo hold or equipment bay).
[0059] As discussed above, a PEM (Proton Exchange Membrane) On
Board Inert Gas Generator (OBIGGS) is an electrochemical stack that
consumes water, air, and electricity to generate an inert gas
stream that can be used for Fuel Tank Inerting and/or Cargo Hold
Fire Suppression as described in U.S. Pat. No. 9,623,981 and U.S.
Pat. No. 9,963,792, the contents of which are each incorporated
herein in their entireties. The PEM OBIGGS does not require bleed
air (e.g., in contrast to conventional Air Separation Modules (ASM)
which rely on an air pressure gradient across membranes for
separation). In contrast, the PEM OBIGGS electrochemically depletes
oxygen from air. In brief, the PEM device electrolyzes water at the
anode to generate O.sub.2, liberates electrons, and transports
protons through a polymer electrolyte. At the cathode, the protons
combine with O.sub.2 in air to form water vapor. The depletion of
O.sub.2 thus generates an inert gas consisting of humid nitrogen
and any residual oxygen. The amount of oxygen in the inert gas can
be tailored to the application (e.g., <12% by volume for fuel
tank passivation, <15% for bio-compatible cargo hold fire
suppression, etc.).
[0060] Another system may be a solid oxide (SO) electrochemical gas
separator (SOEGS) cell configured to transport oxygen out of
incoming process air, resulting in inert oxygen-depleted air. The
use of SOEGS cells is beneficial for purposes of energy efficiency
and lower system weight. In addition, the replacement of
ozone-depleting organic halides such as Halon that are used as fire
extinguishing agents on aircraft with an inert gas generation
system is more environmentally benign. In one example
configuration, ceramic solid oxide fuel cells may be leveraged in a
variety of systems (e.g., producing electrical current and
generating inerting gas). In some configurations, both fuel and air
are fed into the cells, resulting in a voltage difference across
the cell that can be used to generate an electric current. In such
configurations, the cathode of the fuel cell is positive, while the
anode of the fuel cell is negative. Further, in some
configurations, solid oxide systems have been used to accomplish
electrolysis of water or carbon dioxide, splitting the water or
carbon dioxide into separated components. Various example SOEGS
systems are disclosed and discussed in U.S. Patent Application
Publication Nos. 2017/0167036 A1 and 2018/0140996, the disclosures
of which are incorporated herein by reference in their
entireties.
[0061] As noted above, the systems described herein can be used to
generate inert gas, oxygen, and/or power, depending on a mode of
operation and the specific configuration of the generator.
Supplying such gas or power to locations on an aircraft may require
various considerations, such as locations of water, gases, powered
electronics, protected spaces (e.g., cargo holds, fuel tank
ullages, etc.). At times, specifically for vehicle critical
systems, the proximity of the generator may be important to ensure
prompt generation of the inert gas, oxygen, and/or power.
[0062] Embodiments of the present disclosure are directed to
positioning systems in locations to generate gases or power
substantially or relatively close to a point of use--rather than
the necessarily most convenient location on an aircraft (e.g., due
to space, components, etc.). Furthermore, embodiments described
herein are directed to providing redundancy of systems (i.e.,
redundant inert gas, oxygen, and/or power generation systems, as
described above).
[0063] Vehicle critical systems, as used herein, are systems that
are necessary for safe operation of a given vehicle. Such systems
can be electrical, mechanical, or generation systems, necessary to
ensure safe and continued operation of the vehicle. For example, if
the vehicle is an aircraft, "flight critical" ("FC") systems on an
aircraft are the most safety-critical systems. If FC systems were
to fail, malfunction, or be absent from the aircraft, then an
unsafe condition due to an undersized engine shutdown may occur, or
a catastrophic failure resulting in serious damage or loss of the
aircraft may ensue. As will be appreciated by those of skill in the
art, an aircraft cannot depart without the FC systems being
operational. Examples of FC systems include, but are not limited
to, the following systems: communication, traffic collisions
avoidance, emergency power, fire suppression, O.sub.2 generation
(e.g., for tactical aircraft). Furthermore, in addition to FC
systems, an aircraft may have Mission critical ("MC") systems that
are important or necessary to meet mission objectives, but are less
safety-critical than FC systems. One non-limiting example of an MC
system is a fuel tank inerting system. Those of skill in the art
will appreciate that other systems may be designated FC or MC,
depending on the nature of the system, the specific aircraft,
flight requirements, mission requirements, use requirements, etc.
Thus, the above described FC and MC systems are not intended to be
limited to these specific examples. However, it will be appreciated
that certain systems are not FC or MC, such non-critical systems
include, but are not limited to, in-flight-entertainment systems,
galley equipment, etc.
[0064] In accordance with some embodiments of the present
disclosure, an electrochemical device with at least two stacks on
board is provided. The electrochemical device provides for
redundant functionality, with single- or dual-mode envisioned (gas
separator and/or fuel cell). The electrochemical device may be a
PEM system or a SO system, as discussed above. Electrochemical
systems are differentiated by the electrolytes employed in such
systems. By definition, electrolytes transport ions but not
electrons. Embodiments of the present disclosure are discussed with
respect to two different types of electrolytes: (1) a polymeric
variety that conducts protons, also known as a proton exchange
membrane (PEM), and (2) a ceramic variety that conducts ions,
either oxygen ions or protons, which is usually known as solid
oxide (SO). It will be appreciated that other systems, mechanisms,
and/or configurations may be employed without departing from the
scope of the present disclosure.
[0065] In accordance with some embodiments of the present
disclosure, the redundant electrochemical systems can provide power
and/or gas generation in at least two modes of operation: a first
mode being electrolytic operation providing power/gas to fuel tank
inerting systems, core flight systems, and O.sub.2 generation
(e.g., for life support), and a second mode being fuel cell
operation providing power/gas to fuel tank inerting systems, core
flight systems, and emergency power systems (EPS).
[0066] Turning now to FIG. 5, a schematic illustration of a vehicle
500 (illustrated as an aircraft) having multiple, redundant
electrochemical devices 502a-c for electrical power and/or inert
gas generation in accordance with an embodiment of the present
disclosure is shown. In this illustrative embodiment, a first
electrochemical device 502a and a second electrochemical device
502b are each located within a mechanical bay of the vehicle 500
(e.g., as described above). The first and second electrochemical
devices 502a, 502b may be configured as redundant systems that are
each arranged to supply, at a minimum, FC and/or MC inert gas,
oxygen, and/or electrical power generation. That is, each of the
first electrochemical device 502a and the second electrochemical
device 502b may be arranged to supply 100% of the FC and/or MC
needs of an aircraft, if the other of the first electrochemical
device 502a or the second electrochemical device 502b fails.
However, during normal operation, each of the first and second
electrochemical devices 502a-b can be operated at less than full
capacity (as the two electrochemical devices can be operated
jointly with each at less than full operating potential). Operation
at partial load is typically more efficient in both modes of
operation. This increased efficiency is due to the characteristics
of performance typical of electrochemical systems.
[0067] Further, as illustratively shown in FIG. 5, a third
electrochemical device 502c is arranged on a wing of the vehicle
500. The third electrochemical device 502c can be an additional
redundant electrochemical device, which can also be configured to
supply 100% of the FC and/or MC needs of the vehicle 500. That is,
the combination of the three redundant electrochemical devices
502a-c can provide the inert gas, oxygen, and/or electrical power
needs of the vehicle 500 during normal use, with each redundant
electrochemical device 502a-c operating at less than full capacity.
However, if one or more of the redundant electrochemical devices
502a-c fails, the remaining redundant electrochemical devices
502a-c can be operated at greater capacity to supply, at a minimum,
FC and/or MC needs of the vehicle 500.
[0068] It is noted that the third electrochemical device 502c is
located within the wing of the vehicle 500. That is, the third
electrochemical device 502c is arranged at a location different
from the other electrochemical devices 502a-b. By arranging at
least one electrochemical device at a different location, in
addition to providing safety (e.g., if a failure happens in
proximity to another electrochemical device) the location may be
optimal for the specific needs of the vehicle 500. For example, one
or both of the first and second electrochemical devices 502a-b may
be configured to supply inerting gas for a fire suppression system
of a cargo hold of the vehicle 500. Further, one or both of the
first and second electrochemical devices 502a-b may be configured
to supply electrical power to one or more FC and/or MC electrical
components. At the same time, the third electrochemical device 502c
may be configured to supply inert gas to a fuel tank ullage located
in a wing of the vehicle 500 and/or can be configured to supply
electrical power to components within the wing of the vehicle 500
(e.g., controllers and/or components of flight control surfaces
such as ailerons, flaps, etc.).
[0069] As shown in FIG. 5, the first and second electrochemical
devices 502a-b are co-located (e.g., same bay or proximal to each
other) and the third electrochemical device 502c is distributed
(e.g., located away from the other electrochemical devices). As
such, as noted above, an electrochemical device of the present
disclosure can be located close to a point of use. During normal
operation, each of the electrochemical devices 502a-c can be
operated at less than full capacity to provide inert gas, oxygen,
and/or electrical power in proximity to the specific
electrochemical device. However, if one or more of the
electrochemical devices fails, the remaining one or more
electrochemical devices may be operated at a higher capacity to
account for the failure of the other device(s).
[0070] Although shown with three electrochemical devices on the
vehicle 500, such configuration is not to be limiting. For example,
at a minimum, two electrochemical devices may be arranged on an
aircraft in a redundant manner, whether co-located or distributed.
However, three or more electrochemical devices may be employed in
this manner, without departing from the scope of the present
disclosure. The electrochemical devices can be different sizes in
order to cover various demands throughout a mission. For example,
inert gas for fuel tank inerting is highest during descent when the
demanded flow rate is larger than inert gas required for cargo-fire
suppression low rate of discharge systems (CFS-LRD). In one
non-limiting embodiment, an electrochemical system is sized to
generate electricity in a first mode of operation (e.g., fuel cell
mode for emergency power). In a second mode of operation of the
same system, the electrochemical system generates more than enough
inert gas to cover fuel tank inerting requirements as well as
CFS-LRD.
[0071] As noted above, the electrochemical devices can be
configured to generate inert gas and/or electrical power, depending
on a mode of operation. As noted above, fuel tank inerting is not
vehicle-critical, so redundancy is not required for this system. In
contrast, fire suppression, emergency electrical power, and O.sub.2
generation for life support systems on tactical aircraft are
vehicle (e.g., mission) critical. The electrochemical devices
provide redundancy for these vehicle critical systems.
[0072] Turning now to FIG. 6, a schematic illustration of a vehicle
600 (illustrated as an aircraft) having a redundant electrochemical
device system in accordance with an embodiment of the present
disclosure is shown. In this non-limiting embodiment, a first
electrochemical device 602a and a second electrochemical device
602b are arranged to supply inert gas, oxygen, and/or power to
various locations on the vehicle 600. The electrochemical devices
602a-b each configured to output inert gas to a common inert gas
distribution manifold 604 to supply inert gas to fuel tank ullages
of one or more fuel tanks 606. Further, a common O.sub.2
distribution manifold 608 is provided to supply oxygen to a life
support system (or to another system or location on or off the
vehicle 600). Accordingly, in this embodiments, the fuel tank
inerting system of the vehicle 600 and the oxygen system of the
vehicle 600 each have a redundant electrochemical device system
connected thereto, such that failure of one of the electrochemical
devices 602a, 602b does not impact the FC or MC systems of the
aircraft.
[0073] Furthermore, in this illustrative embodiment, the redundant
electrochemical device system is configured to output power to an
electrical bus 610 (e.g., DC bus). The electrochemical devices
602a, 602b can thus be operated in a gas generation mode to
generate inert gas and/or oxygen, or in a power or fuel cell mode
to generate electrical power to be supplied on the electrical bus
610 to one or more electrical components. In a fuel cell mode, the
electrochemical devices 602a, 602b can be configured to generate
inert gas to be supplied to a fuel tank inerting system and/or to a
fire suppression system.
[0074] In some embodiments, the common inert gas distribution
manifold 604 contains one or more valves or other control elements
that allow selective routing of inert gas to a fire suppression
system 612 (e.g., in a cargo hold) or to a fuel tank inerting
system (including fuel tanks 606). In normal operation, for
example, a first valve 614 may be normally open, to allow for inert
gas to be directed to the fuel tanks 606 and a second valve 616 may
be normally closed. However, because fire suppression is a
vehicle-critical function, the valves 614, 616 can be reversed if
the second electrochemical device 602b fails. That is, the first
electrochemical device 602a can be configured to provide inert gas
to the fire suppression system 612, if the other (second)
electrochemical device 602b fails. However, if the first
electrochemical device 602a fails, because fuel tank inerting is
not vehicle (mission or flight) critical, the mission can be
continued without adjusting the position/state of the valves 614,
616. Furthermore, the common inert gas distribution manifold 604
can include at least one check valve (not shown) to prevent any
fuel vapors from entering the common O.sub.2 distribution manifold
608. Although not shown, the illustrative system shown in FIG. 6
can include power lines into the electrochemical devices 602a,
602b, supply lines into the electrochemical devices 602a, 602b for
reactants (e.g., air, water, hydrogen, oxygen, etc.), etc.
[0075] Turning now to FIG. 7, a schematic illustration of a vehicle
700 (illustrated as an aircraft) having a redundant electrochemical
device system in accordance with an embodiment of the present
disclosure is shown. In this non-limiting embodiment, a first
electrochemical device 702a and a second electrochemical device
702b are arranged to supply inert gas, oxygen, and/or power to
various locations on the vehicle 700. In this embodiment, a fire
suppression system 712 can receive inert gas from either
electrochemical device 702a, 702b directly. As shown, a first valve
714 is configured to selectively isolate the first electrochemical
device 702a from the fire suppression system 712. The second
electrochemical device 702b is connected to the fire suppression
system 712.
[0076] Each of the electrochemical devices 702a-b may be connected
to a common O.sub.2 distribution manifold 708 to supply oxygen to a
life support system (or to another system or location on or off the
vehicle 700). In this embodiment, however, there is no common
inerting gas manifold. That is, only the first electrochemical
device 702a is configured to provide inert gas to fuel tank ullages
to one or more fuel tanks 706 of the vehicle 700. A second valve
716 is arranged to selectively close the fuel tank inerting system
from the first electrochemical device 702a, to ensure that inert
gas is provided from the first electrochemical device 702a to the
fire suppression system 712 in the event of a failure of the second
electrochemical device 702b. In some embodiments, both a check
valve (i.e., one-way) and a selective operation (e.g., on/off
valve) can be implemented. The specific valve/control arrangement
is not to be limited to illustrations herein, but rather any type
of flow control can be employed without departing from the scope of
the present disclosure. It is noted that in some embodiments, the
electrochemical devices 702a-b may be connected to separate O.sub.2
distribution manifolds, and the present illustration is not to be
limiting.
[0077] Accordingly, in this embodiment, the oxygen system of the
vehicle 700 has a redundant electrochemical device system connected
thereto, such that failure of one of the electrochemical devices
702a, 702b does not impact the FC or MC systems of the aircraft.
However, as noted, the fuel tank inerting system does not have a
redundant electrochemical device because such aspect is not MC or
FC. Similar to the embodiment of FIG. 6, in this illustrative
embodiment, the redundant electrochemical device system is
configured to output power to an electrical bus 710 (e.g., DC bus).
The electrochemical devices 702a, 702b can thus be operated in an
electrolytic mode to generate inert gas and/or oxygen, or in a
power or fuel cell mode to generate electrical power to be supplied
on the electrical bus 710 to one or more electrical components. In
a fuel cell mode of operation, the electrochemical devices 702a,
702b may be used to generate an inert gas to be supplied to a fuel
tank inerting system and/or to a fire suppression system.
[0078] In this embodiment, in operation, the first electrochemical
device 702a normally generates inert gas for the fuel tanks 706. In
some embodiments, the first electrochemical device 702a may have a
larger stack than the second electrochemical device 702b because
fuel tank inerting may require more inert gas than fire suppression
systems depending on a phase of flight of an aircraft. As noted,
the first electrochemical device 702a is outfitted with valves that
allows selective routing of inert gas to the fire suppression
system 712 (e.g. in a cargo hold) and/or to a fuel tank inerting
system including the fuel tanks 706. As discussed, fire suppression
is a vehicle-critical function, and thus the first suppression
system 712 is provided with redundant electrochemical devices.
[0079] Although illustratively shown in FIGS. 6-7 with the
electrochemical devices located within the central portion of the
aircraft, in alternative embodiments, one or more electrochemical
devices may be located elsewhere on the aircraft. For example, if
one or more electrochemical devices are configured to generally
supply inerting gas to fuel tanks, such electrochemical devices may
be arranged in or on the wings of the aircraft (e.g., as shown in
FIG. 5). Further, in some embodiments, an electrochemical device
can be arranged close to the cockpit of an aircraft in order to
supply oxygen for life support and/or to generate and supply
electrical power to vehicle (e.g., flight) critical electrical
components within the cockpit. Thus, the illustrative embodiments
are not to be limiting, but rather are provided for illustrative
and explanatory purposes.
[0080] In the above described embodiments, and in accordance with
embodiments of the present disclosure, a multiple, redundant system
is provided. In the simplest example, with two electrochemical
devices (first and second), each of the first and second
electrochemical devices can be operated in one of two modes
(although additional modes may be employed depending on the
configuration and needs of the vehicle and/or electrochemical
devices). In a first mode of operation of each of the
electrochemical devices, the respective electrochemical devices
operates at less than full capacity and provides inerting gas,
oxygen, and/or electrical power. This first mode of operation may
be employed during normal operation of the vehicle. However, if,
for example, the second electrochemical device fails, the first
electrochemical device can be switched into a second mode of
operation wherein the first electrochemical device provides
inerting gas, oxygen, and/or electrical power to MC and/or FC
components, as needed, to compensate for the failure/loss of the
second electrochemical device. Given that the systems is designed
to be redundant, the second electrochemical device can provide the
compensation for a loss of or failure of the first electrochemical
device. Similarly, such redundancy may be implemented with any
number of redundant electrochemical devices. During the second mode
of operation of a given electrochemical device, the operating
capacity may be increased to generate additional inerting gas,
oxygen, and/or electrical power, as needed. As such, embodiments of
the present disclosure can reduce or eliminate instances where
vehicle operation (or a mission) may be compromised due to the loss
of an electrochemical device.
[0081] Advantageously, embodiments of the present disclosure
provide for redundant and/or optimally positioned back-up and/or
generation systems on vehicles for vehicle critical
components/systems (e.g., flight or mission critical for aircraft).
For example, advantageously, embodiments provided here can locate
or position sources of inert gas, oxygen, and/or power generation
close to a point of use. Further, according to some embodiments,
backup systems are provided to enable a mission to continue even
after one device or system fails, thus extending the flight
capabilities of aircraft. Moreover, in some embodiments, if a
redundant system is sized to be capable of generating and/or
providing full power/inert gas requirements to another system, then
operating each redundant system at less than full power (operate at
partial capacity) can be more efficient. Furthermore, if one of the
redundant systems fails, the remaining systems can be operated at
full capacity to account for the loss of one of the other redundant
systems.
[0082] The term "about", if used, is intended to include the degree
of error associated with measurement of the particular quantity
based upon the equipment available at the time of filing the
application. For example, "about" can include a range of .+-.8% or
5%, or 2% of a given value.
[0083] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the present disclosure. As used herein, the singular forms "a",
"an" and "the" are intended to include the plural forms as well,
unless the context clearly indicates otherwise. It will be further
understood that the terms "comprises" and/or "comprising," when
used in this specification, specify the presence of stated
features, integers, steps, operations, elements, and/or components,
but do not preclude the presence or addition of one or more other
features, integers, steps, operations, element components, and/or
groups thereof.
[0084] While the present disclosure has been described with
reference to an exemplary embodiment or embodiments, it will be
understood by those skilled in the art that various changes may be
made and equivalents may be substituted for elements thereof
without departing from the scope of the present disclosure. In
addition, many modifications may be made to adapt a particular
situation or material to the teachings of the present disclosure
without departing from the essential scope thereof. Therefore, it
is intended that the present disclosure not be limited to the
particular embodiment disclosed as the best mode contemplated for
carrying out this present disclosure, but that the present
disclosure will include all embodiments falling within the scope of
the claims.
* * * * *